绘制因果图的包（->软件测试技术）

Question

是否有用于绘制因果图的包或包扩展（请参阅下面的屏幕截图中的原子元素）。

如果没有包，有人可以解释如何使用 tikz 实现这一点，尤其是否定符号和曲线。

Answer 1

你可以这样做：

\documentclass[border=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning,decorations.markings,automata,angles,quotes}

\tikzset{
  myneg/.style={
    decoration={
      markings,
      mark=at position 0.5 with 
        {\draw (0,0) arc (0:180:#1) (0,0) arc (180:360:#1);}
    },
    postaction=decorate
  },
  myneg/.default=6pt,
  mynode/.style={
    draw,
    circle,
    minimum size=20pt
  }
}

\begin{document}

\begin{tikzpicture}
\node[mynode] (a) at (0,0) {$a$};
\node[mynode] (b) at (3,0) {$b$};
\draw 
  (a) -- (b) node[above=8pt,midway,font=\scshape] {identity};
\begin{scope}[xshift=5cm]
\node[mynode] (a) at (0,0) {$a$};
\node[mynode] (b) at (3,0) {$b$};
\draw[myneg] 
  (a) -- (b) node[above=8pt,midway,font=\scshape] {not};
\end{scope}
\begin{scope}[yshift=-4cm]
\node[mynode] (a) at (0,2) {$a$};
\node[mynode] (b) at (0,0) {$b$};
\node[mynode] (c) at (0,-2) {$c$};
\node[mynode] (d) at (3,0) {$d$};
\coordinate (aux) at (d.west);  
\foreach \Value in {a,b,c}
  \draw (\Value) -- (aux);
\path 
  pic[draw,angle radius=35pt,"\raisebox{20pt}{$\lor$}",
    angle eccentricity=1.25] 
  {angle=a--aux--c};  
\path (a) -- (d) node[above=12pt,midway,font=\scshape] {or};  
\end{scope}
\begin{scope}[xshift=5cm,yshift=-4cm]
\node[mynode] (a) at (0,2) {$a$};
\node[mynode] (b) at (0,-2) {$b$};
\node[mynode] (c) at (3,0) {$c$};
\foreach \Value in {a,b}
  \draw (\Value) -- (c.west);
\path 
  (a) -- (c) 
  node[above=12pt,midway,font=\scshape] {and};
\node[left=of c,font=\scshape] {$\land$};  
\end{scope}
\end{tikzpicture}

\end{document}

使用修饰（在库的帮助下）获得了否定decorations.markings，并且“OR”的弧是在angles库的帮助下生成的。

当然，根据实际的应用程序类型，您可以为节点使用额外的库，例如automata或chains。

另一个示例展示了否定和或路径的实际作用：

\documentclass[border=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning,decorations.markings,automata,angles,quotes}

\tikzset{
  myneg/.style={
    decoration={
      markings,
      mark=at position 0.5 with 
        {\draw (0,0) arc (0:180:#1) (0,0) arc (180:360:#1);}
    },
    postaction=decorate
  },
  myneg/.default=6pt,
  mynode/.style={
    draw,
    circle,
    minimum size=20pt
  }
}

\begin{document}

\begin{tikzpicture}[node distance=1cm and 2cm]
\node[mynode] (b) at (0,0) {$b$};
\node[mynode,above=of b] (a) {$a$};
\node[mynode,below=of b] (c) {$c$};
\node[mynode,right=of b] (d) {$d$};
\node[mynode,above right=of d] (e) {$e$};
\node[mynode,below right=of d] (f) {$f$};
\coordinate (aux) at (d.west);  
\foreach \Value in {a,b,c}
  \draw (\Value) -- (aux);
\path 
  pic[draw,angle radius=35pt,"\raisebox{20pt}{$\lor$}",
    angle eccentricity=1.25] 
  {angle=a--aux--c};  
\draw[myneg]
  (d) -- (e);
\draw[myneg]
  (d) -- (f);
\end{tikzpicture}

\end{document}